Author

Hood Chatham <roberthoodchatham@gmail.com> 2024-10-07 16:12:41 +0200

Parents

0f366d5

Tree

2cc254c

Refactor Python startup code to prepare for Python pools

For Python pools, we have to run `instantiateEmscriptenModule` before we bind
the feature flags and set up the global scope and module registry. We will need
to bundle all of the relevant code into a single script with no imports. This PR
makes most of the typescript changes that will be needed to enable this.

I split part of `python.ts` into a new file called `emscriptenSetup.ts` which
intended for execution as part of the pool. To do this, `emscriptenSetup.ts`
cannot import anything that uses C++ APIs. After this PR, it nearly satisfies
this constraint except for the use of UnsafeEval by `newWasmModule`. I will fix
that in a followup.

Aside from moving code from `python.ts` to `emscriptenSetup.ts`, the code
changes relate to the fact that `emscriptenSettings` cannot receive information
from snapshot.ts. We have to cause the relevant effects dynamically. Instead of
setting `INITIAL_MEMORY`, we use `Module.growMemory`. We patch Emscripten to
read the value of `Module.noInitialRun` directly before calling `main()`
(instead of loading it early and ignoring subsequent changes). And instead of
calling `preloadDynamicLibs()` from a prerun hook, we use `addRunDependency()`
to stall the initialization of the runtime until we have a chance to load the
dynamic libraries.